Question

Emissive power of an ideal black body at ${127}^{o}C$ is $E$. The temperature at which it increases to $102\%$ is

• A. $400K$
• B. $100K$
• C. $402K$
• D. $502K$

Answer 1

The correct option is C $402K$

Emissive power $,E=-A{T}^4$

$\Rightarrow E=-A{\left(400\right)}^n$

when power increase to $102\%$

$\Rightarrow -A{T}^n=-A{\left(400\right)}^n\times 102$

$\Rightarrow T^n={\left(400\right)}^n\times 102$

$\Rightarrow T={\left(1.02\right)}^{0.25}\times 400$

$\Rightarrow T=401.98k$

Hence, the answer is $401.98k.$